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One of the values of biodiversity is that it may provide 'biological
insurance' for services currently rendered by domesticated species or
technology. We used crop pollination as a model system, and investigated
whether the loss of a domesticated pollinator (the honey bee) could be
compensated for by native, wild bee species. We measured pollination
provided to watermelon crops at 23 farms in New Jersey and Pennsylvania,
USA, and used a simulation model to separate the pollen provided by honey
bees and native bees. Simulation results predict that native bees alone
provide sufficient pollination at > 90% of the farms studied. Furthermore,
empirical total pollen deposition at flowers was strongly, significantly
correlated with native bee visitation but not with honey bee visitation. The
honey bee is currently undergoing extensive die-offs because of Colony
Collapse Disorder. We predict that in our region native bees will buffer
potential declines in agricultural production because of honey bee losses.

"We measured pollination provided to watermelon crops at 23 farms in New Jersey and Pennsylvania,USA, and used a simulation model to separate the pollen provided by honey bees and native bees."

I am wondering how she figured the pollination contribution of native vs honeybees for the simulation model. A model is only as good as the variables input. Is this study published anywhere?
Elsewhere we read that native pollinators are becoming rarer due to pesticide use and loss of habitat.
If these farms were not dependent on honeybees why not pollinate some farms with the native bees, some with the honeybees? Why the need for a simulation at all?
Sheri

Those are good questions Sheri. I had to read it again to figure some of that out. Its complicated, but I will try and summarize some parts of it.

Firstly, you can't really remove honeybees or native bees from a farm to test it as you suggest, but you could do it in a greenhouse. However its not going to be a real situation and no management systems are already figured out for most native bees.

The word 'similuation' makes the study sound like its all programming work, but this study had a very large amount of field data collected. 2 kinds of data collected where relative to the simulation.

One was pollinator visitation rate to flowers. Visitation rate was measured by bee visits per flower per time. Bee species where blocked into 5 species: Honey Bees then the native bees=(Bombus and carpenter bees, other large bees, green bees, and small bees.)

The second was per-visit pollen deposition. Unopened femal flowers where bagged with mesh. Then the virgin flowers where offered to individual bees naturally foraging. The bee was identified to the above species group, and the flower was then removed to determine the number of watermelon pollen grains on the stigma.

These where craftily feed into a program and the output was the distribution of the number of pollen grains deposited on a flower over its lifetime by the various groups of bees.

Different types of figureing for experimental error was done to make the estimates conservative.

This data was then analyzed statistically.

Obviously this is an extremely lacking interpretation of the paper, but thats why its 8 pages instead of a few paragraphs.

Elsewhere we read that native pollinators are becoming rarer due to pesticide use and loss of habitat.

thats exactly right. This paper is from some of the same folks that are doing similar work in California where the results of habitat loss and other farming practices have made very clear negative impacts on pollinators. This is the first study in the east where agriculture is not as intensive and the climate and other factors are different. In my view, the pollinator friendly attributes of the farms in this study is an indicator that the landscape in intensive agriculture areas could benifit from a more diverse habitat to increase native pollinators, decrease dependence on honeybees, and make farming more sustainable. That said, honeybees will always be needed for agriculture. Obviously they wouldn't be used in the east if they weren't essential. But the effect that native bees have on pollination in addition to honey bees is extremely significant and becomes clear reading the other studies in this field.

The study is published in Ecology Letters

"a forum for the very rapid publication of the most novel research in ecology".

looks like Cornell is also going to be doing some research in this area. this post-doc position was just advertised.

Posted October 3, 2007

Postdoctoral Associate – Entomologist/Insect Ecologist – Research will identify how pollination services by native bees can be maximized in cucurbit crops given the current difficulty and expense of relying on pollination by managed European honey bees. Landscape features, nectar and pollen sources, agricultural practices and other factors will be identified for conserving or increasing populations of the most important native bee species. Ph.D. in entomology or related discipline required. Background in pollination ecology, bee identification, landscape ecology and cucurbit production are desired. Available January 1, 2008, but can be filled later. Appointment is for 1 yr, with potential for second year. Salary $35,000/yr plus benefits. Cornell University is an equal opportunity, affirmative action educator and employer. Send cover letter, CV and contact information for three references to: Dr. Brian A. Nault, Dept. of Entomology, Cornell Univ., NYSAES, 630 W. North St., Geneva, NY 14456; phone: 315-787-2354 or email: ban6@cornell.edu.

Thanks Michael.
I was hoping to read the paper but it needs a subscription.:mad:

I thought the post re the California tomato pollination was interesting, and telling. Perhaps one of the costs of farming will eventually be maintaining a large green space for native pollinators.
This would be a huge cost in farm environments such as in California with large expanses of orchards and row crops. Fact is, honeybees would have to be rare and costly indeed to entice the naturalization of the needed acreage. No wonder our native pollinators are in trouble. Another argument against mono culture.
Sheri

This would be a huge cost in farm environments such as in California with large expanses of orchards and row crops.

It would seem that way, however there are studies that contradict that. Depending on the circumstances, green spaces in farms have shown to create economic benefit in studies. Beneficial insects that control pest populations and pollinate need habitat to exist. Farms have left rows fallow and done other similar things and end up with the same monetary profit with less work primarily being attributed to less problems with pest species.

Now the first similar restoration study to look specifically at native bees is underway in California at a place called Butler Farm. Its mentioned in the Xerces Society publication Farming for Bees. It includes about 1.5 miles of linear habitat and is rolled in with a watershed restoration project to provide a benefit for neighboring farms. There are so many variables to consider in a cropping system, you have to look at the big picture. Some things that seem economically prohibitive at first often are not due to the quantity of benefits.

I guess time will tell. I haven't seen anything else about the study at Butler Farm. Do you know anything about that aszalan?